Citizen Miyano BNJ-42SY

$230,000 - $320,000 Updated 2026-03-19

Key Specifications

max bar capacity sp1

42 mm (1.65 in)

max bar capacity sp2

42 mm (1.65 in)

max machining length

100 mm (3.94 in)

main spindle speed

60 - 6,000 RPM

main spindle power

15/11 kW (20/15 hp)

sub spindle speed

50 - 5,000 RPM

Overview

The Citizen Miyano BNJ-42SY is a twin-turret, twin-spindle fixed-headstock CNC lathe with Y-axis that represents the full-capability model in the BNJ-42 platform. The SY designation adds off-center milling to the twin-turret simultaneous machining architecture, enabling complete mill-turn operations on complex parts from 42 mm bar stock with maximum productivity.

The main spindle (SP1) delivers 15/11 kW (20/15 hp) from 60 to 6,000 RPM, while the sub-spindle (SP2) provides 7.5/5.5 kW (10/7.5 hp) at 5,000 RPM. Both spindles accept 42 mm bar stock for full-diameter capability on both ends. The upper turret (HD1) has 12 stations with live tools at 6,000 RPM, and the lower turret (HD2) has 8 stations with live tools at 3,000 RPM. Y-axis travel of +/-40 mm on the upper turret enables off-center machining.

Axis travels measure 165 mm on X1, 246 mm on Z1, 85 mm on X2, and 590 mm on Z2. Maximum machining length is 100 mm. The 590 mm Z2 travel provides generous clearance for part transfer and extended backworking operations. The Mitsubishi M80W dual-path control manages the complex synchronization between four independent axis groups.

At 5,300 kg with a floor space of 2,840 x 1,560 mm, the BNJ-42SY is built for production environments where cycle time directly impacts profitability. The twin-turret architecture delivers 30-50% cycle time reduction on parts with balanced front-and-back complexity, while the Y-axis adds milling capability for flats, keyways, hexagonal profiles, and cross-drilling at off-center positions.

The BNJ-42SY is the performance ceiling of Citizen's 42 mm fixed-headstock platform for shops that need both twin-turret simultaneous machining and Y-axis milling. Automotive transmission components, medical device housings, hydraulic manifold fittings, and industrial connectors with complex milled and turned features on both ends are the primary application base.

Full Specifications

Parameter	Value
Max Bar Capacity Sp1	42 mm (1.65 in)
Max Bar Capacity Sp2	42 mm (1.65 in)
Max Machining Length	100 mm (3.94 in)
Main Spindle Speed	60 - 6,000 RPM
Main Spindle Power	15/11 kW (20/15 hp)
Sub Spindle Speed	50 - 5,000 RPM
Sub Spindle Power	7.5/5.5 kW (10/7.5 hp)
Upper Turret Stations	12
Lower Turret Stations	8
Upper Turret Live Tool Speed	6,000 RPM
Lower Turret Live Tool Speed	3,000 RPM
Y Axis Travel	80 mm (+/-40 mm)
Travel X1	165 mm (6.50 in)
Travel Z1	246 mm (9.69 in)
Travel X2	85 mm (3.35 in)
Travel Z2	590 mm (23.23 in)
Max Drilling Hd1	13 mm
Max Drilling Hd2	10 mm
Machine Weight	5,300 kg
Floor Space	2,840×1,560mm(Without Chip Conveyor)
Machine Height	1,700 mm
CNC Control	Mitsubishi M80W dual-path
Items	BNJ-42S6
Machining Capacity	Standard Turning Length
Standard Machining Diameter	SP1/SP2
Spindle	Spindle Speed Range
Sp2	JPN, H-S16, DIN171E
Type Of Collet Chuck	SP1
Type Of Power Chuck	SP1/SP2
Turret	Type of Turret
Hd2	M10×1.0
Revolving Tools	Maximum Number of Revolving Tools
Spindle Speed Range	HD1
Maximum Drilling Diameter	HD1
Maximum Tapping Diameter	HD1
Slide Stroke	Turret Slide Stroke
Z1 Axis	246mm
Spindle Slide Stroke	X2 axis
Z2 Axis	590mm
Motors	Spindle Motor
Sp2 Cs	7.5/5.5kw(15min./Cont.)
Machine Dimensions	Machine Height
Sliding Headstock Type	A20
Bar Work	BNC42
Turning Machine	BNA42CY
High Precision Turning Machines	BNA42SY
Multi Station Machining Cell	MC20 III
Standard Turning Length Sp1 Sp2	100mm
Standard Machining Diameter Sp1 Sp2	51mm Dia./42mm Dia.
Spindle Speed Range Sp1	50 - 5,000min-1
Spindle Speed Range Sp2	50 - 5,000min-1
Type Of Collet Chuck Sp1	H-S22, DIN177E
Type Of Collet Chuck Sp2	JPN, H-S16, DIN171E
Type Of Power Chuck Sp1 Sp2	6"/5" Hollow
Type Of Turret Hd1	12st.
Type Of Turret Hd2	8st.
Maximum Number Of Revolving Tools Hd1	Max.12
Maximum Number Of Revolving Tools Hd2	Max.4
Spindle Speed Range Hd1	6,000min-1
Maximum Drilling Diameterhd1	13mm Dia.
Maximum Drilling Diameterhd2	10mm Dia.
Maximum Tapping Diameter Hd1	M12×1.75
Maximum Tapping Diameter Hd2	M10×1.0
Turret Slide Stroke X1 Axis	165mm
Turret Slide Stroke Z1 Axis	246mm
Spindle Slide Stroke X2 Axis	85mm
Spindle Slide Stroke Z2 Axis	590mm
Spindle Motor Sp1 Cs	15/11kw(15min./Cont.)
Spindle Motor Sp2 Cs	7.5/5.5kw(15min./Cont.)
Spindle Speed Range Hd2	3,000min-1
Maximum Drilling Diameter Hd1	13mm Dia.
Turret Slide Stroke Y Axis	±40mm
Maximum Drilling Diameter Hd2	10mm Dia.
Inquiries	Feel free to get in touch with us by phone or online if you have any questions or need advice about any of our products or services.

Specifications sourced from cmj.citizen.co.jp — verified 2026-03-28

Strengths & Limitations

Strengths

True dual-turret independence with Y-axis combines simultaneous machining and off-center milling for the most capable machine in the BNJ-42 lineup
15/11 kW main spindle delivers 20/15 hp for aggressive roughing in steel and stainless at the full 42 mm bar diameter
Full 42 mm bar capacity on both spindles ensures complete front-and-back machining without sub-spindle diameter limitations
Y-axis travel of +/-40 mm enables off-center milling for flats, keyways, hexagonal profiles, and complex cross-drilling patterns
590 mm Z2 travel provides generous clearance for part transfer and extended backworking operations
12+8 turret configuration with 6,000 RPM upper turret live tools handles the most demanding mill-turn applications

Limitations

5,300 kg weight and 2,840 x 1,560 mm footprint requires significant floor space and foundation work compared to single-turret BNA machines
3,000 RPM lower turret live tool speed limits backworking milling operations to lighter cross-drilling and tapping
Twin-turret Y-axis programming is among the most complex in the Miyano lineup, requiring advanced multi-path programmers
Higher acquisition cost than single-turret alternatives requires consistent high-volume work to justify the investment

Best For

Automotive transmission component production where twin-turret simultaneous machining with Y-axis shaves critical seconds from high-volume cycle times Medical device housing manufacturers producing complex parts with milled features on both ends that benefit from dual-turret independence Hydraulic manifold and fitting production running large quantities with balanced front-and-back complexity including off-center features Industrial connector manufacturers producing parts from 42 mm bar with cross-drilling, milling, and threading on both ends Production environments seeking the maximum capability in the 42 mm fixed-headstock class for complex mill-turn parts

Frequently Asked Questions

01 What does a new Citizen Miyano BNJ-42SY cost?

New BNJ-42SY6 machines typically range from $230,000 to $320,000 depending on tooling, high-pressure coolant, bar feeder, and automation options. The Y-axis adds approximately $30,000-$50,000 over the base BNJ-42S model.

02 How does the BNJ-42SY compare to the BNA-42DHY?

The BNJ-42SY has larger turrets (12+8 vs 8+6), more spindle power (15/11 kW vs 7.5/5.5 kW), Y-axis on the upper turret, full 42 mm bar on both spindles, and longer Z2 travel (590 mm vs 360 mm). The BNA-42DHY is lighter (3,100 kg vs 5,300 kg) and more compact. Choose the BNJ for maximum capability; choose the DHY for compact installation.

03 What CAM software supports BNJ-42SY programming?

Esprit, GibbsCAM, Mastercam, and NCSIMUL all support dual-path programming for the BNJ-42SY's Mitsubishi M80W control. Offline simulation with collision detection is strongly recommended for optimizing simultaneous turret operations.

04 Can the BNJ-42SY handle chucker work?

Yes. Both spindles accept power chucks (H-S20 on SP1, H-S16 on SP2) for castings, forgings, and pre-cut blanks. The machine handles bar-fed and chucker work interchangeably, with most shops maintaining setups for both modes.